1. Field of the Invention
The present invention relates to a speed governor of an engine, particularly to a mechanical type speed governor provided with flyweights.
2. Description of the Prior Art
In a mechanical type speed governor of an engine, a plural of flyweights is opened or moved outward in the radial direction by centrifugal force, whereby a throttle opening position or an amount of fuel can be controlled. As a support structure of the flyweight, for example, there is a conventional structure in which the flyweight is pivotally supported on a gear provided on a cam shaft via a support pin or the like. According to this structure, there is no need for newly providing a governor shaft and governor drive gears. However, there is a case where a speed governor cannot be provided on the cam shaft due to various devices installed in the cam shaft or a shape of the cam shaft itself.
In an utility engine for agriculture described in Japanese Patent Laying-Open No. 2000-88057, one end of a crankshaft serves as a direct output shaft part, and furthermore, a flywheel, a recoil starter, and the like are installed in the other end of the crankshaft. Thus, in terms of a space or a structure, it is difficult to provide the speed governor on the crankshaft. Therefore, as shown in FIG. 21, a governor shaft 101 is newly arranged in parallel to a crankshaft 100, a driven gear 102 exclusive to the speed governor is provided on this governor shaft 101, and further, a drive gear 103 to be meshed with the driven gear 102 is provided on the crankshaft 100, so that a flyweight (not shown) for the speed governor is supported on the driven gear 102.
When the governor shaft, the driven gear, and the drive gear exclusive to the speed governor are provided as in the conventional example, the number of parts is increased, time and efforts are required for an assembling task, and size of crankcase and the engine is increased.
An object of the present invention is to provide a speed governor of an engine which facilitates assembling the speed governor into the engine without newly providing a governor shaft and governor drive gears, so as to reduce the number of parts of the engine and decrease size of the engine.